The present invention relates to a life estimation device for an engine which collects data on operation parameters, such as engine rotational speed, which values change when an engine of a construction machine or other machine is operating, and estimates the life of the engine based on the data on the operation parameters. The present invention also relates to a life estimation device for an engine which collects data on the operation parameters, such as engine rotational speed, which values change when a machine having a heat source, such as an engine, is operating, and estimates the life of the engine of the machine based on the data on the operation parameters.
It is extremely important to accurately estimate the time of overhaul for inspections and maintenance services of construction machines.
Because if the time of overhaul is accurately estimated, serious accidents, such as major damage to the engine, can be prevented by executing maintenance at an appropriate time. Also, estimating the time of overhaul accurately makes maintenance planning possible. In other words, the advantages are that accurate production planning, including vehicle schedule planniing, is possible, preparing parts required for overhaul at the required time is possible, and management of mechanics is easier.
In construction machines, however, the operating conditions of the engine greatly differ depending on the operating environment and operation of the individual user, and the time required for overhaul greatly differs even if the same model and same type engine is used. A simple determination of the overhaul time of an engine is not possible.
Therefore, it is required to accurately estimate the time of overhaul, that is, the life of the engine for an individual construction machine and individual engine.
The life of an engine is determined by the actual damage quantity exerted on the engine; that is, the accumulated load applied to the engine.
However, a numeric representation of the damage quantity exerted on the engine is actually difficult, so an indirect numeric representation of the damage quantity exerted on the engine based on the operating status of the engine at respective occasions has been attempted.
In other words, conventionally, the operating status of the engine is periodically recorded by a service tool, and the time of overhaul is determined by comparing the recorded value with the preset threshold value. For example, the valve clearance is actually measured, and this measured value is compared with the threshold value as instructed in the shop manual, and the time of overhaul is judged when the measured value exceeds the threshold value. The sound of the engine is also listened to, and the time of overhaul is judged by whether an abnormal sound is heard.
However, such operating states of the engine at each occasion do not accurately indicate the damage quantity exerted on the engine, and judgment on whether it is the time of overhaul greatly depends on the skill and experience of the mechanic. Therefore, the estimation of the time of overhaul is not always accurate.
Another attempt is to collect not only the operating states of the engine on respective occasions, but also to collect data on the engine (e.g. horse power of the engine) over a long period of time, determining the time of overhaul from the time-based changes.
However, it is difficult to represent the damage quantity actually exerted on the engine by numerics to determine the life of the engine. In other words, if the engine is continuously operated with a predetermined load (e.g. engine is always operated at a rated point), the damage quantity can be estimated relatively easily, assuming that the damage quantity increases in proportion to time, but if the load of the engine fluctuates as time elapses, numeric representation of the damage quantity is difficult. As a result, the time of overhaul has been determined based on the skill and experience of the mechanic.
In this way, a conventional method for estimating the time of overhaul, where judgment is not based on numeric representation of damage actually exerted on the damage, but depends on the skill of the mechanic, was not very accurate.
Because of this, it was always possible that an appropriate overhaul could not be taken at the necessary time, and a serious accident, such as major damage to the engine, occurred.
With the foregoing in view, it is the first object of the present invention to accurately represent the damage quantity exerted on the engine by numerics, so that the life of the engine can be automatically and accurately estimated without expert skills.
The life of the engine is determined not only by the above mentioned accumulation of load but also by the time the engine is exposed to heat.
In this case, there are two types of damage exerted on the engine, one is the drop in strength which occurs when the engine is exposed to high temperature. This is called xe2x80x9cheat temperature fatiguexe2x80x9d. The other damage is heat deterioration which is caused by repeated rise and fall of the temperature. This is called xe2x80x9cthermal fatiguexe2x80x9d.
Numeric representation of such damage quantity exerted on the engine due to heat was as difficult as the above mentioned numeric representation of damage quantity exerted on the engine due to the accumulation of load.
With the foregoing in view, it is the second object of the present invention to accurately represent the damage quantity exerted on a machine having such a heat source as an engine (e.g. power train which is influenced by the heat of the engine itself, or heat generated by the engine) by numerics, so that the life of the machine having a heat source can be automatically and accurately estimated without expert skills.
The first aspect to the sixteenth aspect of the present invention are to achieve the first object.
The first aspect of the present invention is a life estimation device for an engine which collects data of operation parameters which values change when the engine is operating and estimates a life of the engine based on the data of the operation parameters, comprising:
load map setting means (4) for selecting one operation parameter or two or more operation parameters indicative of a load exerted on the engine, and dividing a value of the one operation parameter or combinations of values of the two or more operation parameters into a plurality of levels, so as to set a one-dimensional or two- or more dimensional load map for indicating a distribution of magnitude of the load exerted on the engine;
operation parameter detection means (2, 3) for detecting the values of the operation parameters;
time integration means (7, 8), by detecting the operation parameters by the operation parameter detection means until a predetermined time elapses, for integrating a time during which operation parameter values belonging to the respective level are detected for each level of the load map;
weight setting means (5) for setting a weight in accordance with the load of the respective level for each level of the load map;
damage quantity calculation means (9) for determining the weighted integration time for each level of the load map by weighting the integration time integrated by the time integration means in accordance with the weight set by the weight setting means, and calculating an actual damage quantity exerted on the engine until the predetermined time elapses based on the integration time weighted for each level of the load map;
correspondence relationship setting means (6) for presetting a correspondence relations hip between a magnitude of the damage quantity and a length of life by pre-operating the engine; and
life estimation means (10) for determining a life corresponding to the actual damage quantity calculated by the damage quantity calculation means from the correspondence relationship preset by the correspondence relationship setting means, and outputting the determined life as the estimated life of the engine.
According to the configuration of the first aspect of the present invention, the engine rotational speed Ne and the rack position of the governor (fuel consumption) V are selected as the operation parameters indicative of the load exerted on the engine, as shown in FIG. 3, and the combinations of the operation parameter values Ne and V are divided into a plurality of levels B1, B2, . . . B16. In this way, the two-dimensional load map B which indicates the distribution of the load exerted on the engine is set.
And these operation parameter values Ne and V are detected.
As FIG. 4 shows, these operation parameters Ne and V are detected until the predetermined time xcfx84 elapses, and time xcex1i when the values of the operation parameters belonging to the respective level Bi (i=1-16) are detected is integrated for each level B1, B2, . . . B16 of the load map B.
Also, as FIG. 5 shows, a weight ki in accordance with the load at the respective level Bi is set for each level B1, B2, . . . B16 of the load map B.
And by executing weighting xcex1ixc2x7ki, in accordance with the above mentioned preset weight ki for the above mentioned integrated integration time xcex1i, the weighted integration time xcex1ixc2x7ki is determined for each level B1, B2, . . . B16 of the load map B, and actual damage quantity "sgr"=xcexa3xcex1ixc2x7ki exerted on the engine until the predetermined time xcfx84 elapses is calculated based on the weighted integration time xcex1ixc2x7ki for each level Bi of the load map B.
As FIG. 6 shows, the correspondence relationship L2 between the magnitude of damage quantity a and length of life H is preset by pre-operating the engine.
Therefore, the life H1 corresponding to the above calculated actual damage quantity "sgr"1 is determined from the above mentioned preset correspondence relationship L2, and the determined life H1 is output as the estimated life of the engine.
In this way, the damage quantity "sgr"1 exerted on the engine is accurately represented by numerics and the life H1 of the engine can be automatically and accurately estimated without expert skills.
The second aspect of the present invention is the first aspect of the present invention, characterized in that the two operation parameters indicative of the load exerted on the engine are an engine rotational speed Ne and a torque or a horse power of the engine. And the two-dimensional load map of the engine rotational speed Ne and the torque or the horse power of the engine is set.
The third aspect of the present invention is the first aspect of the present invention, characterized in that the values of the operation parameters Ne and V are detected at each predetermined interval xcex94t, as shown in FIG. 7. By counting the number of times ni when the operation parameter values Ne and V belonging to the respective level Bi for each level B1, B2, . . . B16 of the load map B until the predetermined time xcfx84 elapses (total number of times of detection: N), the time when the operation parameter values Ne and V belonging to the level Bi are detected, that is, xcex1i=(ni/N)xc2x7100, is integrated for each level B1, B2, . . . B16 of the load map B, as shown in FIG. 3.
The fourth aspect of the present invention is the first aspect of the present invention, characterized in that the integration time xcex1i is reset each time the predetermined time xcfx84 elapses, so as to re-estimate the life of the engine each time the predetermined time xcfx84 elapses.
Abrasion of the moving parts of the engine is promoted more as the change of engine load and change of engine rotational speed increases. Therefore, the damage quantity actually exerted on the engine differs depending on the fluctuation quantity of the engine load and the fluctuation quantity of the engine rotational speed.
The fifth aspect to the tenth aspect of the present invention are based on the view where the difference in the fluctuation quantity of the engine load and the fluctuation quantity of the engine rotational speed greatly influence the life of the engine in general and of the parts constituting the engine.
So, the fifth aspect of the present invention is a life estimation device for an engine which collects data of operation parameters which values change when the engine is operating, and estimates a life of the engine based on the data of the operation parameters, comprising:
operation parameter detection means (2, 3) for selecting one operation parameter or two or more operation parameters indicative of a load exerted on the engine or an engine rotational speed and detecting values of the selected operation parameters at each predetermined interval;
fluctuation quantity calculation means (28) for calculating a fluctuation quantity of the operation parameters per unit time based on the values of the operation parameters detected by the operation parameter detection means at each predetermined interval;
fluctuation quantity map setting means (25) for setting a fluctuation quantity map indicative of a distribution of magnitude of the fluctuation quantity of the operation parameters per the unit time;
frequency measurement means (29, 30) for measuring a frequency of calculating the respective magnitude of the fluctuation quantity until a predetermined time elapses for each magnitude of the fluctuation quantity of the fluctuation quantity map;
weight setting means (26) for setting a weight for each magnitude of the fluctuation quantity of the fluctuation quantity map;
damage quantity calculation means (34) for determining the weighted frequency for each magnitude of the fluctuation quantity of the fluctuation quantity map by weighting the frequency measured by the frequency measurement means in accordance with the weight set by the weight setting means, and calculating an actual damage quantity exerted on the engine until the predetermined time elapses based on the weighted frequency for each magnitude of the fluctuation quantity of the fluctuation quantity map;
correspondence relationship setting means (2) for presetting a correspondence relationship between the magnitude of the damage quantity and a length of life by pre-operating the engine; and
life estimation means (31) for determining the life corresponding to the actual damage quantity calculated by the damage quantity calculation means from the correspondence relationship preset by the correspondence relationship setting means, and outputting the determined life as the estimated life of the engine.
According to the configuration of the fifth aspect of the present invention, the engine rotational speed Ne and the rack position of the governor (fuel consumption) V are selected as the operation parameters indicative of the load exerted on the engine and the engine rotational speed, and these operation parameter values Ne and V are detected at each predetermined interval xcex94t, as shown in FIG. 7.
And as FIG. 10 shows, the fluctuation quantity of the operation parameter Ne per unit time is calculated based on the values of the operation parameters which are detected sequentially.
And the fluctuation quantity map HS indicative of the distribution of the magnitude of the fluctuation quantity xcex94Nej of the operation parameters per unit time is set.
Then, as FIG. 13 shows, the frequency xcex1j to calculate the fluctuation quantity of the respective magnitude xcex94Nej (j=1-4) is measured until the predetermined time xcfx84 elapses, for each magnitude of the fluctuation quantity xcex94Nej, that is, xcex94Ne1, xcex94Ne2, xcex94Ne3 and xcex94Ne4 of the fluctuation quantity map HS.
On the other hand, as FIG. 21 shows, weights k1, k2, k3 and k4 are set for each magnitude of the fluctuation quantity xcex94Nej, that is, xcex94Ne1, xcex94Ne2, xcex94Ne3 and xcex94Ne4 of the fluctuation quantity map HS.
And the above mentioned measured frequency xcex1j is weighted in accordance with the above set weight kj, so that the weighted frequency kjxc2x7xcex1j is determined for each magnitude of the fluctuation quantity xcex94Nej of the fluctuation quantity map HS, and the actual damage quantity xcex3f=xcexa3kjxc2x7xcex1j exerted on the engine until the predetermined time xcfx84 elapses is calculated based on the weighted frequency kjxc2x7xcex1j of each magnitude of the fluctuation quantity xcex94Nej of the second map HS.
On the other hand, the correspondence relationship between the magnitude of the damage quantity xcex3t=xcexa3kjxc2x7xcex2j and the length of life Lt is preset by pre-operating the engine.
Then the life Lf corresponding to the above calculated actual damage quantity xcex3f is determined from the above mentioned preset correspondence relationship between xcex3t and Lt (Lf=(xcex3t/xcex3f)xc2x7Lt), and the determined life Lf is output as the estimated life of the engine.
The sixth aspect of the present invention is a life estimation device for an engine which collects data of operation parameters which values change when the engine is operating, and estimates a life of the engine based on the data of the operation parameters; comprising:
a first map setting means (24) for setting one operation parameter or two or more operation parameters indicative of a load exerted on the engine or an engine rotational speed and setting a one-dimensional or two- or more dimensional first map indicative of a distribution of magnitude of the load exerted on the engine or a magnitude of the rotational speed by dividing a value of the one operation parameter or combinations of values of two or more operation parameters into a plurality of levels;
operation parameter detection means (2, 3) for detecting the operation parameter values at each predetermined interval;
judgment means (27) where which level of the first map the operation parameter values, which are detected by the operation parameter detection means at each predetermined interval, belong to, is judged at the predetermined interval;
fluctuation quantity calculation means (28) where based on the level judged sequentially by the judgment means, the fluctuation width between the levels which fluctuated per unit time is calculated as the fluctuation quantity of the operation parameters per unit time;
a second map setting means (25) for setting a second map indicative of the distribution of magnitude of the fluctuation quantity of the operation parameters per the unit time;
frequency measurement means (29, 30) for measuring a frequency of calculating the respective magnitude of the fluctuation quantity until a predetermined time elapses for each magnitude of the fluctuation quantity of the second map;
weight setting means (26) for setting a weight for each magnitude of the fluctuation quantity of the second map;
damage quantity calculation means (34) for determining the weighted frequency for each magnitude of the fluctuation quantity of the second map by weighting the frequency measured by the frequency measurement means in accordance with the weight set by the weight setting means, and calculating an actual damage quantity exerted on the engine until the predetermined time elapses based on the weighted frequency for each magnitude of the fluctuation quantity of the second map;
corresponding relationship setting means (26) for presetting a correspondence relationship between the magnitude of the damage quantity and a length of life by pre-operating the engine; and
life estimation means (31) for determining the life corresponding to the actual damage quantity calculated by the damage quantity calculation means from the correspondence relationship preset by the correspondence relationship setting means, and outputting the determined life as the estimated life of the engine.
According to the configuration of the sixth aspect of the present invention, the engine rotational speed Ne and the rack position of the governor (fuel consumption) V are selected as the operation parameters indicative of the load exerted on the engine and the engine rotational speed, and combinations of these operation parameter values Ne and V are divided into the plurality of levels B1, B2, . . . B16, as shown in FIG. 10. In this way, the two-dimensional first map B indicative of the distribution of the degree of load exerted on the engine and the degree of the engine rotational speed is set.
And as FIG. 7 shows, these operation parameter values Ne and V are detected at each predetermined interval xcex94t.
Then which level Bi (i=1-16) of the first map B the operation parameter values Ne and V detected at each predetermined interval xcex94t belong to is judged at each predetermined interval xcex94t.
And as FIG. 10 shows, based on the levels B7 and B8 judged sequentially, the fluctuation width xcex94Ne1 between both levels B7 and B8, which fluctuated per unit time, is calculated as the fluctuation quantity xcex94Ne of the operation parameter Ne per unit time.
Then as FIG. 11 shows, the second map HS indicative of the distribution of the magnitude of the fluctuation quantity xcex94Nej of the operation parameter per unit time is set.
And as FIG. 13 shows, the frequency xcex94j to calculate the fluctuation quantity of the respective magnitude xcex94Nej (j=1-4) is measured until the predetermined time xcfx84 elapses for each magnitude of the fluctuation quantity xcex94Nej, that is, xcex94Ne1, xcex94Ne2, xcex94Ne3 and xcex94Ne4, of the second map HS.
On the other hand, as FIG. 21 shows, weights K1, K2, K3 and K4 are set for each magnitude of the fluctuation quantity xcex94Nej, that is, xcex94Ne1, xcex94Ne2, xcex94Ne3 and xcex94Ne4, of the second map HS.
And the above mentioned measured frequency xcex1j is weighted in accordance with the above set weight kj, so that the weighted frequency kjxc2x7xcex1j is determined for each magnitude of the fluctuation quantity xcex94Nej of the second map HS, and the actual damage quantity xcex3f=xcexa3kjxc2x7xcex1j exerted on the engine until the predetermined time xcfx84 elapses is calculated based on the weighted frequency kjxc2x7xcex1j for each magnitude of the fluctuation quantity xcex94Nej of the second map HS.
On the other hand, the correspondence relationship between the magnitude of the damage quantity xcex3t=xcexa3kjxc2x7xcex2j and the length of life Lt is preset by pre-operating the engine.
Then the life Lf corresponding to the above calculated actual damage quantity xcex3f is determined from the above mentioned preset correspondence relationship between xcex3t and Lt (Lf=(xcex3t/xcex3f)xc2x7Lt), and the determined life Lf is output as the estimated life of the engine.
The seventh aspect of the present invention is the fifth aspect of the present invention, characterized in that the selected operation parameters are the engine rotational speed Ne or the torque T or the horse power PS of the engine.
The eighth aspect of the present invention is the sixth aspect of the present invention, characterized in that the first map B is a two-dimensional map of the engine rotational speed Ne and the torque T or the horse power PS of the engine, and the second map HS is a one-dimensional map of the fluctuation quantity of the engine rotational speed Ne or a one-dimensional map of the fluctuation quantity of the engine torque T or engine horse power PS.
The ninth aspect of the present invention is the fifth aspect or the sixth aspect of the present invention, characterized in that a specified detection range (B15, B16) in accordance with the type of parts constituting the engine is excluded from the detection target range for the operation parameter values Ne and V which are detected at each predetermined interval xcex94t, as shown in FIG. 14, and the life is estimated for each type of parts constituting the engine.
Also the ninth aspect of the present invention is the sixth aspect of the present invention, characterized in that the specified levels B15 and B16 in accordance with the type of parts constituting the engine are excluded from the judgment targets on which level Bi (i=1-16) of the first map B the operation parameter values Ne and V detected at each predetermined interval xcex94t belong to, and the life is estimated for each type of parts constituting the engine.
The tenth aspect of the present invention is the fifth or sixth aspect of the present invention, characterized in that the value of the weight kj is changed in accordance with the type of parts constituting the engine and the life is estimated for each type of parts constituting the engine.
The eleventh aspect of the present invention is the fifth or sixth aspect of the present invention, characterized in that the frequency xcex1j is reset each time the predetermined time xcfx84 elapses, so that the life of the engine is re-estimated each time the predetermined time xcfx84 elapses.
The twelfth aspect of the present invention is a life estimation device for an engine which collects data of operation parameters which values change when the engine is operating and estimates a life of the engine based on the data of the operation parameters, comprising:
a first map setting means (24) for selecting two or more operation parameters indicative of a load exerted on the engine and an engine rotational speed, and setting a first map of two- or more dimensions indicative of a distribution of magnitude of the load exerted on the engine and a magnitude of the rotational speed by dividing combinations of values of the two or more operation parameters into a plurality of levels;
operation parameter detection means (2, 3) for detecting the operation parameter values at each predetermined interval;
judgment means (27) where which level of the first map the operation parameter values, which are detected by the operation parameter detection means at each predetermined interval, belong to, is judged at the predetermined interval;
fluctuation locus calculation means (33), based on the level judged sequentially by the judgment means, for calculating a fluctuation locus between both levels which fluctuated per unit time;
second map setting means (25) for setting a second map indicative of the distribution of types of the fluctuation locus between both levels per the unit time;
frequency measurement means (29, 30) for measuring a frequency of calculating the respective type of the fluctuation locus until a predetermined time elapses for each type of fluctuation locus of the second map;
weight setting means (26) for setting a weight for each type of fluctuation locus of the second map;
damage quantity calculation means (34) for determining the weighted frequency for each type of fluctuation locus of the second map by weighting the frequency measured by the frequency measurement means in accordance with the weight set by the weight setting means, and calculating an actual damage quantity exerted on the engine until the predetermined time elapses based on the weighted frequency for each type of fluctuation locus of the second map;
correspondence relationship setting means (26) for presetting a correspondence relationship between the magnitude of the damage quantity and a length of the life by pre-operating the engine; and
life estimation means (31) for determining the life corresponding to the actual damage quantity calculated by the damage quantity calculation means from the correspondence relationship preset by the correspondence relationship means, and outputting the determined life as the estimated life of the engine.
According to the configuration of the twelfth aspect of the present invention, the engine rotational speed Ne and the rank position of the governor (fuel consumption) V are selected as the operation parameters indicative of the load exerted on the engine and the engine rotational speed, as shown in FIG. 17, and the combinations of these operation parameter values Ne and V are divided into the plurality of levels B1, B2, B3 and B4. In this way, the two-dimensional first map B, indicative of the distribution of the magnitude of the load exerted on the engine and the magnitude of the engine rotational speed, is set.
And as FIG. 7 shows, these operation parameter values Ne and V are detected at each predetermined interval xcex94t.
Then, which level Bi (i=1-4) of the first map B the operation parameter values Ne and V, which are detected at each predetermined interval xcex94t, belong to, is judged at each predetermined interval xcex94t.
And as FIG. 17 shows, based on the levels B3 and B1 judged sequentially, the fluctuation locus between the levels B3xe2x86x92B1 (locus H) which fluctuated per unit time is calculated.
Then as FIG. 18 shows, the second map HS indicative of the distribution of the types of fluctuation locus Mj (M1 (B1xe2x86x92B2), M2 (B1xe2x86x92B3 . . . ) between the levels per unit time, is set.
And the frequency xcex1j of calculating the fluctuation locus Mj (j=1-12) of the respective type is measured until a predetermined time xcfx84 elapses for each type of the fluctuation locus, that is, M1 (B1xe2x86x92B2), M2 (B1xe2x86x92B3)
On the other hand, as FIG. 21 shows, a weight kj is set for each type of fluctuation locus Mj of the second map HS.
And the above mentioned measured frequency xcex1j is weighted in accordance with the above set weight kj, so that the weighted frequency kjxc2x7xcex1j is determined for each type of the fluctuation locus Mj of the second map HS, and the actual damage quantity of xcex3f=xcexa3kjxc2x7xcex1j exerted on the engine until the predetermined time xcfx84 elapses is calculated based on the weighted frequency kjxc2x7xcex1j for each type of fluctuation locus Mj of the second map HS.
On the other hand, the correspondence relationship between the magnitude of the damage quantity xcex3t=xcexa3kjxc2x7xcex2j and the length of the life Lt is preset by pre-operating the engine.
Then, the life Lf corresponding to the above calculated actual damage quantity xcex3f is determined from the above mentioned preset correspondence relationship between xcex3t and Lt (Lf=(xcex3t/xcex3f)xc2x7Lt), and the determined life Lf is output as the estimated life of the engine.
The thirteenth aspect, fourteenth aspect, fifteenth aspect and sixteenth aspect of the present invention correspond to the above mentioned eighth aspect, ninth aspect, tenth aspect and eleventh aspect of the present invention respectively.
The seventeenth aspect to the thirty fifth aspect of the present invention are aspects for achieving the second object.
In the seventeenth aspect to the twenty third aspect of the present invention, the life of the machine is estimated by determining the damage quantity caused by high temperature fatigue in the same manner as the above mentioned first aspect to fourth aspect of the present invention.
In the twenty fourth aspect to the thirty fifth aspect of the present invention, the life of the machine is estimated by determining the damage quantity caused by thermal fatigue, in the same manner as the above mentioned fifth aspect to the eleventh aspect of the present invention.